Winding mechanism



Nov. 7, 1950 W. P. DAWSON WINDING MECHANISM Filed Oct. 50, 1947INVENTOR: Wilfred P. Dawson,

. ATTORNEY.

Patented Nov. 7, 1950 UNITED STATES PATENT OFFICE 6 Claims.

My improvement pertains to a mechanism used for the purpose of windingup motion-picture films on reels, although the device may equally wellbe used for other analogous purposes. The device, in its basic form,includes two elements, the driving element and the driven element, thetwo elements being brought into a frictional engagement to a degreedepending upon the load upon the driven element, that is, the elementsupporting a roll of film. The fact is that the said load varies inpractice. While the engagement and the means to bring about theengagement are perfectly satisfactory where the load is considerable,said means to effect the frictional engagement are not alwayssatisfactory when the load is slight. It must be, also, remembered that,in the initial stages of the winding operation, it is necessary toovercome the inertia of the reel itself, and that the lag of the initialrotary movement of the reel will become immediatelyapparent in thedeficiency of tension in the winding of the film. As a means to cure thedefect, the makers of the present-day equipment suggest the use of anoil of heavy viscosity for the parts to be frictionally engaged, in thebelief that the viscosity ofthe oil would provide a sufficient drag onthe driven part for the purpose of imparting to it a rotary movement.This expedient, however, proved of little value. It is for the purposeof overcoming said objections and deficiencies as above set out, also toeliminate the need of heavy oils that I have improved the conventionaldriving mechanism which is now employed' As a result, I have produced amechanism in which the tension upon a film is substantially uniformduring the whole process of wind ing it up. More specifically, themechanism improved by me will permit the winding of a, film withsufiicient tension in the initial stages of the winding process.

in meeting the problem, I am using certain additional means inconjunction with the basic elements already used in the conventionaldevices. I shall now describe my improvement with reference to theaccompanying drawings in which:

Figure 1 is a perspective view of a winding mechanism with partssupporting it broken oh and disclosing the location of my improvementswith respect to the load-sustaining element therein; Figure 2 is alongitudinal sectional view on line 22 of Figure 1; Figure 3 is atransverse sectional view on line 3-3 of Figure 2; Figure 4 is atransverse sectional view on line 4-4 of Figure 2; similar numeralsrefer to similar parts throughout the several views.

In describing my improvement, I shall start with a bracket composed of awall I I which may be a part of a motion-picture projecting mechanism,the wall including a drum-like boss Ill. The latter is provided with aninternal cylindrical aperture for support of a cylindrical liner I2axially fitted into said boss and retained in place by means of a setscrew 49. Pressed into the liner endwise, is a sleeve 13 extendingoutwardly from said liner and supporting thereon a pulley M which is thedriving element of my device and which includes along hub l5 skirtingsaid sleeve 13 and sloping downwardly in the di rection of boss l0. 1

The hub above referred to terminates in a hard ring l8 which bearsagainst a plurality of ball bearings 19 retained within a race 2| in theinner end of liner [2. On the side remote from the boss, the pulleyincludes a circular, recessed portion l6 axially disposed therein anddefined by an annular shoulder IT. A provision for lubricating theabutting surfaces of hub l5 and sleeve l3 upon which the pulley rotatesis made in said hub by having a hole 5|] drilled therein for admissionof oil as shown in Figure 2, the hole being closed by an oiling plug4-1.

To describe the driven element, I shall start with the shaft 22. Theshaft includes a portion 23 of a reduced diameter for support of a filmreel which is shown in dotted lines indicated by numeral 26, and isprovided with an arm 24, swivelled at 25, the arm serving as a means ofsecuring the film against displacement once it is mounted upon saidreel. At its junction to portion 23, said shaft 22 includes a collar 21made in the form of a truncated cone, the collar being supported byroller bearings 28 a key marked 52 serves to secure the collar to theshaft to cause the collar to rotate with said shaft. It will be notedthat the respective axes of the rollers flare outwardly from thelongitudinal axis of the shaft 22. As a result of that, unless otherwiserestrained, the shaft would have a tendency to move longitudinallyoutwardly from said bearings. An end disc 29, secured to the reducedportion 23 of the shaft, restricts the movement of the shaftinwardly-that is, in the direction away from the reel 26. The end 3| ofthe shaft opposite to that which supports the film is secured to acup-shaped head 32 by means of a set screw 48. The latter includes anaxially disposed hub 34 rising from the bottom of the cup-shapedformation, the hub being bored axially and threaded as shown at 33 inFigure 2 for reception of the above-said. threaded end 3,! of shaft 22.Two

the clutch plate 40 is keyed to the shaft 22 by means of a key 5| so asto rotate therewith.

To support the weight of the head said shaft 22, at that part of itslength where it passes through the center of pulley H3, is provided withball bearings, said ball bearings including an .annular member 43 keyedto the shaft, a plurality of balls 22, and a stationary race 45, thisbeing held within the sleeve It as best shown in Figure 2. i

To conclude the description of the mechanism, I wish to add that acoiled spring 45 is disposed around the shaft 22 between the annularmember 43 on the shaft and between the clutch plate 3%. I wish, also, toadd that the belt by means of which pulley It may be rotated is shown bynumeral 46. I

Having described my above mechanism, I shall now describe itsoperation:.Pulley I4, driven by belt 66, imparts a rotary movement tohead 32 by means of the aforesaid clutch plate 40 and the floating,annular member 4| combined therewith. As the clutch plate is keyed toshaft 22, the rotation of the plate will, naturally, cause the rotationof the shaft. In'orde to effect a frictional engagement between thepulley and the clutch plate 40 through the annular'member 4i thereon,some provision is needed to bring the clutch plate and the annularmember into intimate contact with the faceof the recess [6 in thepulley, preferably a contact under pressure, Normally, this is; broughtaboutby the weight of the film on reel 28, said weight causing aslippage outwardly of the shaft 22, as the cone-shaped ring 21 on theshaft tends to slipin that direction on the outwardly-flaring rollers28. v l However, as indicated in the beginning of the specification, theweight of the reel in the initial. stages of winding up a film is tooslight tobringthe ring M and the clutch plate 40 into a sufficientlyfrictional contact with said pulley, and here it is, where theimprovement devised by me performs its function. The coiled springs 3.8

within apertures 35 in the head 32 carriedby the threaded end of shaft22 bear against the clutch plate 30 by means of balls 39 exerting enoughforceupon the clutch plate and the, annular ring M to cause .asufficient frictional engagement thereof with the pulley 1. 1- so thatthe rotation of the pulley is transmitted to the shaft, supplying enoughtension for; the winding operation of the film. In case of need, thepressure of springs 33 may be. adjusted by means of screws 3].

Subsequently, when the load increases, it is the weight of the load thatwill bring abouta sufficient frictional engagement of the clutch platewith the pulley. When-the load upon the shaft 22 is relieved, the coiledspring 45, hearing against the centralpart of clutch :plate at as bestshown in Figure 2, will shift the plate outwardly in the.

direction of the head 32.

It will be'obvious ,thatsome changesmay be; made in the:construction.of. my. device with- 1 adapted to carry at one end a film reel, a collaradjoining said end of the shaft and being in the shape of a truncatedcone in a frictional engagement with said rollers, a clutch plate,axially "slideable on the shaft for engagement with the face of thedepression in the pulley and rotating thereon with said shaft, acup-shaped head on the other end of the shaft, the head having aplurality of cylindrical apertures parallel to the shaft, a ball withineach aperture bearing against the .clutch plate, each ball being backedup by a coiled spring within the aperture, and an adjustable screwthreaded against said spring.

2. A tensioning device of the kind described including a stationary,tubular support, a beltdriven pulley mounted thereon for rotation, oneface of the pulley having a central depression defined by a shoulderalongthe rim thereof, a shaft axially disposed within the tubularsupport and having at one end means for support of a film reel, acone-shaped collar keyed upon the shaft,

outwardly flaring roller bearings within the tuclosing the aperture onthe side of the clutch plate, the balls bearing against the plate underthe pressure of. the springsto bring the plate into. engagement with therecessed face of the pulley, the shaft being adapted to move axiallypartly out of the flaring-out roller bearings under the weight of theload and the shaft at that end, and a coiled spring on a shaft to urgethe return of the shaft to its normal position on release of said load.

3. A tensioning device of the kind described comprising a bracketincludinga horizontal cylinder, a tubular member axially connected toone end of said cylinder, a belt-driven pulley rotating on said tubularmember, the pulley having a circular depression in one side thereof saiddepression being defined by a shoulder around the rim of the pulley, anoutwardly-flaring bearing at the other end of the cylinder, a shaftaxially-disposed in the cylinder, a substantially conicalcollar on theshaft and within said bearing, 'the'collar when the shaft is loadedhaving a; tendency to slip axially outwardly of said bearing, a clutchplate mounted on the shaft, the.

end .and adjoining the clutch plate, a plurality ofapertures in the headsymmetrically disposed around the axis thereof and parallel thereto, a,ball in, each aperture to bear against the plate,

spring means in each aperture to, urge the ball,

outwardly into contact with the clutch plate, a screw threaded fromoutside into each aperture for adjustment of the tension of the springwithin, and a spring coiled about the shaft and bearing against theclutch plate from the side remote from the head to move the shaft onrelease of the load in the direction of said head to re turn the collarto its normal position within the outwardly flaring bearing.

4. A tensioning device of the kind described including a belt-drivenpulley rotating on a tubular horizontally disposed member and formingthe driving element, a shaft axially disposed within the tubular memberand adapted to carrya load on one end, a cone-shaped collar on the shaftat said load end, a cone-shaped bearing at the outer end of the tubularsupport for engagement with said collar, a spring acting upon the shaftto keep the collar normally within the bearing, but yielding to theoutward pull of the shaft under the weight of the increased loadthereon, a clutch plate mounted on the shaft, adjoining the pulley, andadapted to slide axially thereon to a limited length but keyed to theshaft for rotation therewith, the clutch plate being adapted to slideinto a frictional engagement with the pulley on the axial shift of theshaft outwardly of the conical bearing under the load on the shaft, acup-shaped head mounted on the opposite end of the shaft, the headincluding a plurality of apertures in the direction of the clutch plate,each aperture being closed by a ball and containing a coiled springurging said ball into abutment with said plate, to bring said plate intofrictional engagement with said pulley preliminary to the axial shift ofthe said shaft under the load thereon.

5. A tensioning device of the kind described including a tubularsupporting member, a pulley axially mounted for rotation thereon, anoutwardly flaring bearing within the tubular support at the end remotefrom the pulley, a shaft axially disposed within the tubular support andhaving at one end means to support a load, a conical collar on the shaftand within the outwardly flaring bearing, the shaft being capable ofaxial shifting outwardly of said bearing, a clutch plate on the shaftfacing one side of the pulley for 6 engagement therewith, spring meansto prevent axial shifting of the shaft till the weight of the loadthereon overcomes the tension of said spring, a head at the other end ofthe shaft, the head being provided with a plurality of aperturesparallel to the shaft, a ball closing each aperture on the side of theclutch plate, a spring behind each ball to maintain it in contact withthe plate and to push the plate into engagement with the pulleypreliminary to the shifting of the shaft under the load.

6. A tensioning device of the kind described including a tubularsupporting member, a pulley axially mounted for rotation thereon andhaving on one side a depressed central portion defined by a shoulderalong the rim thereof, an outwardly flaring bearing within the tubularsupport at the end remote from the pulley, a shaft axially disposedwithin the tubular support and having at one end means'to support aload, a conical collar on the shaft and within the outwardly flaringbearing, the shaft being capable of axial shifting outwardly of saidbearing, a clutch plate on the shaft facing one side of the pulley forengagement therewith, a floating friction ring along the marginalportion of the plate and fitting into the depressed central portion inthe pulley, spring means to prevent axial shifting of the shaft till theweight of the load thereon overcomes the tension of said spring, a headat the other end of the shaft, the head being provided with a pluralityof apertures parallelto the shaft, a ball closing each aperture on theside of the clutch plate, a spring behind each ball to maintain it incontact with the plate and to push the plate into engagement with thepulley preliminary to the shifting of the shaft under the load.

, WILFRED P. DAWSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,377,112 Boylan May 3, 19211,398,680 Clayton Nov. 29, 1921,

